I've used these setting on my laptop for quite some time: http://www.vollink.com/gary/deb_wifi.html
It makes switching from wired to wireless a breeze, and works brilliant as long as your wireless is eth1.
I use madwifi-ng so my wireless is ath0. For some reason all the settings don't work and I have to manually start the device every time.
Any clues on how to get ath0 to act the same as eth1?

before I forget: Manualy works when I start the device plugged-in. If I remove the card and replug it, restarting the device and getting it paired with the AP (using WPA) won't work.

Regards

Have you tried substituting every instance of "wlan0" with "ath0" in the scripts and configuration?

Everything needed is set to ath0.

The website that you posted doesn't configure the /etc/ifplugd/ifplugd.action file. Check if it exists. It also uses /etc/default/ifplug. I assume this is used in place of /etc/ifplugd/ifplugd.conf if it doesn't exist. Perhaps there is an /etc/ifplugd/ifplugd.conf present that takes precedence. I looked in the "man ifplugd.conf" and "man ifplugd" man pages and "HOTPLUG_INTERFACES" isn't one of the listed options. Perhaps this variable is used by one of the network or hotplug scripts on your system, in which case you will need to read through your hotplug, ifplugd.action and other scripts in your own system to understand where it is used. Of course, you may have a different version of ifplugd.

By default, ifplugd writes its messages to a log, so you could shut down the wireless card, and re-insert it to see if ifplugd and hotplugd detect it. Actually, this sounds more like something that hotplugd should be doing instead. If the signal drops of for your wireless, but you don't want to rescan for a different network, I don't know what you want triggered. I think it would be more useful for connecting to available networks on the fly, when you are on the road.

The ARGS value given is the default, but I don't know if you want those same values for both eth0 and ath0.
On my laptop, ifplug is started from the /etc/init.d/network script instead of a ifplugd service.

A debian user might be able to provide you with better answers. Given the work ahead, this may be case where you do more work trying to save some work the the work itself. In other words, configuring wireless the standard debian way may turn out to be easier than relying on the solution supplied by a web page.

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Here is a stupid idea. Try reversing the order of the interfaces in /etc/network/interfaces. List ath0 before eth0.